Supposedly the story in To Kill A Mockingbird was taken from a real life incident in another town that she heard about when she was a child.
She and Truman Capote were childhood friends and they both travelled as adults to Kansas together to research a heinous murder that had happened there recently, which became Capote’s “In Cold Blood”................
I don’t think she wanted “The Watchman on the Wall” to be published.
They waited till she died to publish it.
Same thing with Chopin’s last nocture. He didn’t want to publish it, and MOST concert pianists respect the Composer’s wishes.
There’s stuff I’ve written that I hope NEVER sees the light of day! LOL!
She was very important to the book's blossoming, being so respectable and respectful to the Kansans whose perspectives were necessary to tell the tale well - not to mention her same relationship with Capote. I doubt he could have written quite the same masterpiece without having such a great "research assistant."
The character Dill Harris in “Mockingbird” was based on Capote.
Additional info on the Lee / Capote relationship:
https://www.biography.com/authors-writers/harper-lee-truman-capote-friendship-jealously